Retrieving the paleoclimatic signal from the deeper part of the EPICA Dome C ice core
An important share of paleoclimatic information is buried within the lowermost layers of deep ice cores. Because improving our records further back in time is one of the main challenges in the near future, it is essential to judge how deep these records remain unaltered, since the proximity of the b...
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ftunivbruxelles:oai:dipot.ulb.ac.be:2013/218110 2023-05-15T13:47:16+02:00 Retrieving the paleoclimatic signal from the deeper part of the EPICA Dome C ice core Tison, Jean-Louis Jouzel, Jean Stenni, Barbara Johnsen, Sigfús Jóhann S. Masson-Delmotte, Valérie Landais, Amaelle Lipenkov, Vladimir Ya Loulergue, Laetitia Barnola, Jean-Marc Petit, Jean-Robert Delmonte, Barbara De Angelis, Martine Dreyfus, Gabrielle Dahl-Jensen, Dorthe Durand, Gael Bereiter, Bernhard Schilt, Adrian Spahni, Renato Pol, K. Lorrain, Reginald Souchez, Roland Samyn, Denis Littot, Geneviève Wolff, Eric Fischer, Hubertus Hansson, Margareta Bigler, Matthias Udisti, Roberto Wegner, Anna 2015-08 1 full-text file(s): application/pdf http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/218110 https://dipot.ulb.ac.be/dspace/bitstream/2013/218110/3/doi_201737.pdf en eng uri/info:doi/10.5194/tc-9-1633-2015 uri/info:scp/84939813992 https://dipot.ulb.ac.be/dspace/bitstream/2013/218110/3/doi_201737.pdf http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/218110 1 full-text file(s): info:eu-repo/semantics/openAccess The Cryosphere, 9 (4 Econométrie et méthodes statistiques :théorie et applications Géologie et minéralogie info:eu-repo/semantics/article info:ulb-repo/semantics/articlePeerReview info:ulb-repo/semantics/openurl/article 2015 ftunivbruxelles 2022-06-12T21:27:33Z An important share of paleoclimatic information is buried within the lowermost layers of deep ice cores. Because improving our records further back in time is one of the main challenges in the near future, it is essential to judge how deep these records remain unaltered, since the proximity of the bedrock is likely to interfere both with the recorded temporal sequence and the ice properties. In this paper, we present a multiparametric study (δD-δ 18 O ice , δ 18 O atm , total air content, CO 2 , CH 4 , N 2 O, dust, high-resolution chemistry, ice texture) of the bottom 60 m of the EPICA (European Project for Ice Coring in Antarctica) Dome C ice core from central Antarctica. These bottom layers were subdivided into two distinct facies: the lower 12 m showing visible solid inclusions (basal dispersed ice facies) and the upper 48 m, which we will refer to as the "basal clean ice facies". Some of the data are consistent with a pristine paleoclimatic signal, others show clear anomalies. It is demonstrated that neither large-scale bottom refreezing of subglacial water, nor mixing (be it internal or with a local basal end term from a previous/initial ice sheet configuration) can explain the observed bottom-ice properties. We focus on the high-resolution chemical profiles and on the available remote sensing data on the subglacial topography of the site to propose a mechanism by which relative stretching of the bottom-ice sheet layers is made possible, due to the progressively confining effect of subglacial valley sides. This stress field change, combined with bottom-ice temperature close to the pressure melting point, induces accelerated migration recrystallization, which results in spatial chemical sorting of the impurities, depending on their state (dissolved vs. solid) and if they are involved or not in salt formation. This chemical sorting effect is responsible for the progressive build-up of the visible solid aggregates that therefore mainly originate "from within", and not from incorporation processes of debris ... Article in Journal/Newspaper Antarc* Antarctica EPICA ice core Ice Sheet The Cryosphere DI-fusion : dépôt institutionnel de l'Université libre de Bruxelles (ULB) |
institution |
Open Polar |
collection |
DI-fusion : dépôt institutionnel de l'Université libre de Bruxelles (ULB) |
op_collection_id |
ftunivbruxelles |
language |
English |
topic |
Econométrie et méthodes statistiques :théorie et applications Géologie et minéralogie |
spellingShingle |
Econométrie et méthodes statistiques :théorie et applications Géologie et minéralogie Tison, Jean-Louis Jouzel, Jean Stenni, Barbara Johnsen, Sigfús Jóhann S. Masson-Delmotte, Valérie Landais, Amaelle Lipenkov, Vladimir Ya Loulergue, Laetitia Barnola, Jean-Marc Petit, Jean-Robert Delmonte, Barbara De Angelis, Martine Dreyfus, Gabrielle Dahl-Jensen, Dorthe Durand, Gael Bereiter, Bernhard Schilt, Adrian Spahni, Renato Pol, K. Lorrain, Reginald Souchez, Roland Samyn, Denis Littot, Geneviève Wolff, Eric Fischer, Hubertus Hansson, Margareta Bigler, Matthias Udisti, Roberto Wegner, Anna Retrieving the paleoclimatic signal from the deeper part of the EPICA Dome C ice core |
topic_facet |
Econométrie et méthodes statistiques :théorie et applications Géologie et minéralogie |
description |
An important share of paleoclimatic information is buried within the lowermost layers of deep ice cores. Because improving our records further back in time is one of the main challenges in the near future, it is essential to judge how deep these records remain unaltered, since the proximity of the bedrock is likely to interfere both with the recorded temporal sequence and the ice properties. In this paper, we present a multiparametric study (δD-δ 18 O ice , δ 18 O atm , total air content, CO 2 , CH 4 , N 2 O, dust, high-resolution chemistry, ice texture) of the bottom 60 m of the EPICA (European Project for Ice Coring in Antarctica) Dome C ice core from central Antarctica. These bottom layers were subdivided into two distinct facies: the lower 12 m showing visible solid inclusions (basal dispersed ice facies) and the upper 48 m, which we will refer to as the "basal clean ice facies". Some of the data are consistent with a pristine paleoclimatic signal, others show clear anomalies. It is demonstrated that neither large-scale bottom refreezing of subglacial water, nor mixing (be it internal or with a local basal end term from a previous/initial ice sheet configuration) can explain the observed bottom-ice properties. We focus on the high-resolution chemical profiles and on the available remote sensing data on the subglacial topography of the site to propose a mechanism by which relative stretching of the bottom-ice sheet layers is made possible, due to the progressively confining effect of subglacial valley sides. This stress field change, combined with bottom-ice temperature close to the pressure melting point, induces accelerated migration recrystallization, which results in spatial chemical sorting of the impurities, depending on their state (dissolved vs. solid) and if they are involved or not in salt formation. This chemical sorting effect is responsible for the progressive build-up of the visible solid aggregates that therefore mainly originate "from within", and not from incorporation processes of debris ... |
format |
Article in Journal/Newspaper |
author |
Tison, Jean-Louis Jouzel, Jean Stenni, Barbara Johnsen, Sigfús Jóhann S. Masson-Delmotte, Valérie Landais, Amaelle Lipenkov, Vladimir Ya Loulergue, Laetitia Barnola, Jean-Marc Petit, Jean-Robert Delmonte, Barbara De Angelis, Martine Dreyfus, Gabrielle Dahl-Jensen, Dorthe Durand, Gael Bereiter, Bernhard Schilt, Adrian Spahni, Renato Pol, K. Lorrain, Reginald Souchez, Roland Samyn, Denis Littot, Geneviève Wolff, Eric Fischer, Hubertus Hansson, Margareta Bigler, Matthias Udisti, Roberto Wegner, Anna |
author_facet |
Tison, Jean-Louis Jouzel, Jean Stenni, Barbara Johnsen, Sigfús Jóhann S. Masson-Delmotte, Valérie Landais, Amaelle Lipenkov, Vladimir Ya Loulergue, Laetitia Barnola, Jean-Marc Petit, Jean-Robert Delmonte, Barbara De Angelis, Martine Dreyfus, Gabrielle Dahl-Jensen, Dorthe Durand, Gael Bereiter, Bernhard Schilt, Adrian Spahni, Renato Pol, K. Lorrain, Reginald Souchez, Roland Samyn, Denis Littot, Geneviève Wolff, Eric Fischer, Hubertus Hansson, Margareta Bigler, Matthias Udisti, Roberto Wegner, Anna |
author_sort |
Tison, Jean-Louis |
title |
Retrieving the paleoclimatic signal from the deeper part of the EPICA Dome C ice core |
title_short |
Retrieving the paleoclimatic signal from the deeper part of the EPICA Dome C ice core |
title_full |
Retrieving the paleoclimatic signal from the deeper part of the EPICA Dome C ice core |
title_fullStr |
Retrieving the paleoclimatic signal from the deeper part of the EPICA Dome C ice core |
title_full_unstemmed |
Retrieving the paleoclimatic signal from the deeper part of the EPICA Dome C ice core |
title_sort |
retrieving the paleoclimatic signal from the deeper part of the epica dome c ice core |
publishDate |
2015 |
url |
http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/218110 https://dipot.ulb.ac.be/dspace/bitstream/2013/218110/3/doi_201737.pdf |
genre |
Antarc* Antarctica EPICA ice core Ice Sheet The Cryosphere |
genre_facet |
Antarc* Antarctica EPICA ice core Ice Sheet The Cryosphere |
op_source |
The Cryosphere, 9 (4 |
op_relation |
uri/info:doi/10.5194/tc-9-1633-2015 uri/info:scp/84939813992 https://dipot.ulb.ac.be/dspace/bitstream/2013/218110/3/doi_201737.pdf http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/218110 |
op_rights |
1 full-text file(s): info:eu-repo/semantics/openAccess |
_version_ |
1766246839175086080 |